1. Field of the Invention
The present invention relates to a mechanical press drive. More particularly, the present invention relates to a wet or oil shear clutch/brake unit utilizing oil films to eliminate free undamped clearances.
2. Description of the Related Art
Prior wet clutch/brake systems have been used in mechanical presses since they offer the advantage of little or no wear on the plates of the disk stacks and no brake fade. This provides a precise operation of the press and dramatically increases press run time. Furthermore, utilization of multiple disks in a disk stack can be used to greatly reduce the clutch/brake inertia, thereby allowing the mechanical interlocking of clutch and brake without inertia penalty. In addition, the multiple disk surfaces provide precise inching capability.
Particular problems of current wet clutch/brake designs are the utilization of undamped clearances between particular parts. Such undamped clearances create locations of possible wear, such as at clutch drive disks, driven disks, and drive pins.
Other designs of wet clutch/brake units utilize anti-friction thrust bearing to contain or control movement of the actuation plate or piston.
The primary apparatus for storing mechanical energy within a press is a flywheel. The flywheel is usually mounted on one end of the crankshaft and connected by a belt to the output pulley of the motor, such that when the motor is energized, the mass of flywheel rotates continuously. The flywheel and flywheel bearing are normally axially mounted near the drive shaft, crankshaft, or the press frame by use of the quill. The main drive motor replenishes the energy that is lost or transferred from the flywheel during press operations when the clutch engages the flywheel to rotate rotary motion of the flywheel to the crankshaft. During engagement of the clutch, the flywheel drops in speed as the press driven parts are brought up to press running speed.
Additionally, heretofore the lubrication oil utilized within the flywheel bearings, which connect to the flywheel, have used different lubrication oil from that of the friction disks utilized within the clutch/brake unit.